State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Materials, Xiamen University, Xiamen, 361005, China.
Fujian Key Laboratory of Surface and Interface Engineering for High Performance Materials (Xiamen University), Xiamen Key Laboratory of High Performance Metals and Materials (Xiamen University), Xiamen, 361005, China.
Small. 2023 Jul;19(27):e2300605. doi: 10.1002/smll.202300605. Epub 2023 Mar 28.
Hard carbons are deemed as promising anode materials for high-performance potassium-ion battery, but their commercialization is still hindered by the insufficient K transfer kinetics and poor potassiophilicity. Herein, these issues are addressed by improving the wettability of hard carbon, which can be achieved by the introduction of open mesochannels. A series of such hollow mesoporous carbon capsules with different dimensions are synthesized, which exhibit markedly enhanced wettability with electrolyte compared to the microporous counterparts. Various characterizations confirm its effects on promoting the kinetics and potassiophilicity of as-synthesized carbons, which can be additionally improved by S-doping. As a result, the 2D mesoporous carbon anode exhibits excellent rate capability (122.2 mAh g at 4 A g ), high reversible capacity (396.6 mAh g at 0.1 A g after 200 cycles), and outstanding cycling stability (197.0 mAh g at 2 A g after 1400 cycles). In addition, the hollow mesoporous architecture can effectively buffer the volume expansion and thus stabilize the carbon anodes, as visualized by in situ transmission electron microscopy. This work provides new insight for enhanced K storage performance from the perspective of anode wettability with electrolyte, as well as a universal anode design that combines mesochannels architecture with heteroatom doping.
硬碳被认为是用于高性能钾离子电池的很有前途的阳极材料，但由于钾转移动力学不足和亲钾性差，其商业化仍受到阻碍。本文通过改善硬碳的润湿性来解决这些问题，这可以通过引入开放介孔来实现。合成了一系列具有不同尺寸的这种中空介孔碳胶囊，与微孔相比，其对电解质的润湿性明显增强。各种表征证实了其对促进合成碳动力学和亲钾性的影响，通过 S 掺杂可以进一步提高其效果。结果，二维介孔碳阳极表现出优异的倍率性能（在 4 A g 时为 122.2 mAh g ）、高可逆容量（在 0.1 A g 时循环 200 次后为 396.6 mAh g ）和出色的循环稳定性（在 2 A g 时循环 1400 次后为 197.0 mAh g ）。此外，中空介孔结构可以通过原位透射电子显微镜有效地缓冲体积膨胀，从而稳定碳阳极。这项工作从电解质对阳极润湿性的角度为增强钾存储性能提供了新的见解，以及一种将介孔结构与杂原子掺杂相结合的通用阳极设计。
